The invention relates to large-size paneling parts of a thermoplastic synthetic resin for the interior of an automotive vehicle, and to a process for the production thereof.
Panels for the interior of an automotive vehicle along the lines of this invention are understood to mean, in particular, door side parts, headliners (finished dome liners), seat back linings, hat shelves, and side paneling of thermoplastic synthetic resins.
Molded parts as paneling parts in multilayer structure for uses in automotive vehicle interiors have been known for a long time. Such constructions usually consist of a compact supporting member of thermoplastic or thermosetting synthetic resins filled with various materials, or of fibrous starting materials converted, with the aid of suitable resins, into a mechanically load-bearing composite; see, in this connection, for example DOS 3,842,846.
The actual shaping process takes place according to the conventional methods primarily by press-molding, injection molding or in accordance with the RIM and, respectively, RRIM technology.
The basic components display the joint feature that their surface meets only very low decorative requirements. Decorative paneling members are obtained from these molded parts by joining these basic materials with decorative, flat products during the shaping step or also in separate procedures. These decorative, flat products can be imprinted and embossed plastic sheeting as well as woven, knit textiles or nonwovens.
In case a composite is produced by subsequent lamination, the bond between the decorative and, in some cases, soft and elastic top layer and the supporting molded member must be established with simultaneous application of pressure and heat and with the use of a special laminating material.
In pressing processes, flat products are placed into the tool utilized for the shaping step, and thereafter molded parts are produced having decorative, soft and elastic surfaces. Materials that can be processed according to the presently known techniques, and molded parts manufactured pursuant to such techniques exhibit a number of disadvantages:
The pressure to be expended during the press-molding step for the nonwoven mat production step ranges above 5-10 bar, in case of injection molding even above several hundred bar. PA1 The materials employed normally are not based on a unitary polymer type so that the conventional molded parts can be recycled only for low-quality products. PA1 The mass temperature during the shaping step lies, in case of thermoplastic materials, above 180.degree.-200.degree. C. and therefore leads to thermal damage to the top material in cases where the latter is not especially protected, for example by a film, foam sheet, or a similar material. PA1 Molded parts produced in this way must be refinished in a second working step in order to produce a rounded border.